Heat loss occurs preponderantly as a result of radiation from the skin and by sweating with consequent evaporation of the secretion. These processes are functions of the skin and surface circulation. Are they disturbed in our stupors? We find considerable evidence that they are. Flushing or dermatographia occurred in six cases, cold or blue extremities in four cases, greasy skin in four, marked sweating in three, the hair fell out in two cases, while the skin was pathologically dry in one case, in fact there were few patients who showed normal skin function. Circulatory anomalies were also observed. The pulse was very rapid in eleven cases, weak or irregular in two, and slow in one case. All these symptoms are expressions of imbalance in the involuntary nervous system, further evidence of which is found in the rapid respiration of six cases and the shallow breathing of one patient. These pulse and respiration findings are the more striking in that individuals in stupor are, by the very nature of their disease, free from emotional excitement. This imbalance could result from a poverty of circulating adrenalin which is necessary for the activation of the sympathetic nerves. A cause for low suprarenal function is to be found in the apathy of the stupor case. As Cannon and his associates have so conclusively demonstrated, any emotion which was open to investigation resulted in an increase of adrenalin output. As our emotions are constantly operating during the day--and often enough during sleep as well in connection with dreams--we must presume that emotional stimulus is a normal excitant for the production of adrenalin. It is therefore inconceivable that the blood could receive its normal supply of adrenalin with an apathy of the degree seen in stupor unless some purely hypothetically substitutive excitant were found.